1. Field of the Invention
The invention relates generally to systems and methods for selective control of fluid flow into a production string in a wellbore. In particular aspects, the invention relates to devices and methods for actuating flow control valves in response to increased water or gas content in the production fluids obtained from particular production zones within a wellbore. In other aspects, the invention relates to systems and methods for monitoring flow rate or flow density at completion points and adjusting the flow rate at individual production points in response thereto.
2. Description of the Related Art
During later stages of production of hydrocarbons from a subterranean production zone, water or gas often enters the production fluid, making production less profitable as the production fluid becomes increasingly diluted. For this reason, where there are several completion nipples along a wellbore, it is desired to close off or reduce inflow from those nipples that are located in production zones experiencing significant influx of water and/or gas. It is, therefore, desirable to have a means for controlling the inflow of fluid at a particular location along a production string.
A particular problem arises in horizontal wellbore sections that pass through a single layer of production fluid. If fluid enters the production tubing too quickly, it may draw down the production layer, causing nearby water or gas to be drawn down into the production tubing as well. Inflow control devices are therefore used in association with sand screens to limit the rate of fluid inflow into the production tubing. Typically a number of such inflow governing devices are placed sequentially along the horizontal portion of the production assembly.
The structure and function of inflow control devices is well known. Such devices are described, for example, in U.S. Pat. Nos. 6,112,817; 6,112,815; 5,803,179; and 5,435,393. Generally, the inflow control device features a dual-walled tubular housing with one or more inflow passages laterally disposed through the inner wall of the housing. A sand screen surrounds a portion of the tubular housing. Production fluid will enter the sand screen and then must negotiate a tortuous pathway (such as a spiral pathway) between the dual walls to reach the inflow passage(s). The tortuous pathway slows the rate of flow and maintains it in an even manner.
Inflow control devices currently lack an acceptable means for selectively closing off flow into the production tubing in the event that water and/or gas invades the production layer. Additionally, current inflow control devices do not have an acceptable mechanism for bypassing the tortuous pathway, so as to increase the production flow rate. It would be desirable to have a mechanism for selectively closing as well as bypassing the inflow control device.
The present invention addresses the problems of the prior art.